Release 6.18.2: Added Italian translations for standard mail folder names

[changerequest]

Italian is added to the translations for Open-Xchange. The configuration file /opt/open-xchange/etc/admindaemon/User.properties is extended with the Italian translations for the standard mail folder names:

# Italiano

SENT_MAILFOLDER_IT_IT=Posta inviata
TRASH_MAILFOLDER_IT_IT=Cestino
DRAFTS_MAILFOLDER_IT_IT=Bozze
SPAM_MAILFOLDER_IT_IT=Posta Indesiderata
CONFIRMED_SPAM_MAILFOLDER_IT_IT=Posta indesiderata accertata
CONFIRMED_HAM_MAILFOLDER_IT_IT=Posta attendibile accertata